Dear Cecil,
I have been pondering the significance of the asterix and pound buttons on touch tone phones but cannot determine their original purpose. It’s not as though the creators would have known that there would be voice-mail and interactive phone services in the future.
Answer if you can please!
No matter how badly I want to laugh at the form of this post, the content is just soooo good that I can’t! Great question! Did a search and couldn’t come up with anything?
“How’d you get your mind to tilt like your hat?”
-The Thrashing Doves
They were originally intended to facilitate the first Call Waiting service. I can clearly recall the magazine ad that explained their function:
What I probably should have mentioned is that the magazine was Games, and the ad was a “Find the Fake Ad” offering for that month. Thought it was hilarious. 
I worked for Bell-Northern Research (Canadian equivalent of Bell Labs) at the time touch-tone was still in its infancy, and the answer is: yes, they DID think that uses for the * and # buttons would come in time. Of course, the buttons weren’t added just because of that – it just seemed easier to use a standardized 12-key layout than a customized 10-key layout. There was some experimentation: 10 buttons in a circle (emulating the dial), 10 buttons in 2 rows of 5 (too wide or too tall), and even the current layout, but omitting the * and # buttons – but none of these were finally adopted. The touch-tone dial works by combining two different tones to identify each key, and the 3x4 arrangement allows the 12 tones to come from 7 generators: 1 for each row and column. Yes, you could use the same 7 generators to produce only 10 tones, but why not go for the max and just add two “unused” keys?
And by the way, we were told at the time that we were supposed to call # an “octothorpe” instead of a “number” or “pound” sign. Oh well, at least the keyboard layout caught on…
Computers in the future may weigh no more than 15 tons.
-Popular Mechanics, 1949
I too recall from my youth that they were put there for “Future Use.” Just like my VCR has a smart card slot for future use.
Octothorpe,won gold medals in the 1908 Olympics for arm wrestling and the octathalon. The medals were stripped when it was determined that professional moluscs were disqualified from the Olympics.This was later determined to be a blatant act of speciesism and the medals were reinstated in 1968. lets see Thorpe won TWO golds in 1912 for the PENTathalon and the DECatholon, his daughters name is No Ten O Quah. Nope it just won’t work.AHA the info about Thorpe is from People Magazine of 1/8/96,there. But look at this; “…Bell Labs engineer, Don Macpherson, … felt the need for a(n)… unambiguous name for the # symbol… it had eight points, so ought to start with octo-. He was … active in a group…trying to get the…medals of… Jim Thorpe returned…” http://quinion.com/words/weirdwords/ww-oct1.htm
“Pardon me while I have a strange interlude.”-Marx